In the construction industry, narrow beams of collimated light in the form of laser beams are used in instruments termed "laser-leveling devices" for establishing reference lines and planes such as for accurate placement and alignment of building floors, ceilings, and walls.
Methods for producing reference lines and planes using laser beams have varied, but the preferred method has been to radially sweep a laser beam by use of an optical prism, an optical "cone," or other type of optical beam deflector that can be rotated independently of a stationary laser source. Because of their sophistication, such deflectors are typically expensive. Representative prior-art devices for such purposes are disclosed in U.S. Pat. Nos. 3,462,845 to Matthews, 3,579,846 to Catherin, and 3,822,943 to Mason.
The establishment and maintenance of an accurately horizontal or vertical swept laser beam has been the subject of much research and development. In many instances, any of various "auto-leveling" components are employed, as disclosed in U.S. Pat. Nos.: 4,767,208; 3,426,144; 3,471,234; and 4,679,937. Unfortunately, conventional auto-leveling, as disclosed in the foregoing references, requires optical components made with very small tolerances, electronic sensors, and/or extensive use of sophisticated dampening devices. These components, together with expensive beam deflectors, render many types of laser-leveling devices too costly for many small contractors and builders.
U.S. Pat. No. 4,973,158 to Marsh discloses a laser-leveling device comprising a laser diode mounted to a rotatable shaft. Power is supplied to the laser diode from a stationary source. Thus, this apparatus requires an electric "slip ring" to transfer power from the stationary source to the rotating laser. Unfortunately, slip rings are inherently unreliable. Another disadvantage with this apparatus is that the laser source cannot be detached from the shaft for use as a laser level, for producing a stationary laser line, or for hand-held use as a pointer or the like.
Yet another disadvantage of prior-art laser devices of the type used in construction and related arts is that such devices are limited to producing substantially straight lines, not tracings of other geometric profiles.
Thus, there is a need for a laser instrument for tracing reference lines that has sufficient accuracy and reliability for use by small contractors and do-it-yourself homeowners, but is low in cost. There is also a need for such a system having greater utilitarian flexibility for a variety of uses such as for use as a hand-held laser pointer and generator of projected tracings of laser light in a variety of geometric patterns.